Tic Tac Toe - a learning exercise...

The purpose of this game is a coding exercise for my beginning Visual Basic classes.
It includes basic form object layout, code structure tips, decision blocks, use
of CSS, and refactor to OOP class.

This version is the first refactoring of the original. Duplicated code in button
event handlers is shifted to Sub or Function. This refactoring may still result
in other duplicated code that is unknown in the event handlers, but further refactoring
will clean this up.